N-pyridinyl[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide herbicides

ABSTRACT

Substituted N-pyridinyl[1,2,4]triazolo[1,5-c]-pyrimidine-2-sulfonamide compounds, such as N-(2-fluoro-4-methyl)-7-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide, were prepared by condensation of a 2-chlorosulfonyl[1,2,4]triazolo[1,5-c]pyrimidine compound, such as 2-chlorosulfonyl-7-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine, with a substituted 3-aminopyridine compound, such as 3-amino-2-fluoro-4-methylpyridine, and found to possess herbicidal utility.

BACKGROUND OF THE INVENTION

The present invention relates to substituted sulfonamide compounds, to herbicidal compositions containing the compounds, and to the utility of the compounds for the control of unwanted vegetation.

The control of unwanted vegetation by means of chemical agents, i.e., herbicides, is an important aspect of modern agriculture and land management. While many chemicals that are useful for the control of unwanted vegetation are known, new compounds that are more effective generally, are more effective for specific plant species, are less damaging to desirable vegetation, are safer to man or the environment, are less expensive to use, or have other advantageous attributes are desirable.

A number of sulfonamide compounds, including certain substituted [1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide compounds (U.S. Pat. No. 4,954,163) and [1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds (U.S. Pat. No. 5,010,195 and European Application 244,948), are known and are known to possess herbicidal activity, especially on broadleaf weeds.

SUMMARY OF THE INVENTION

It has now been found that certain N-pyridinyl[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds are potent herbicides for the control of unwanted vegetation, have desirable crop selectivity and have favorable toxicological and environmental attributes. The compounds are effective on grassy as well as broadleaf weeds.

The invention includes N-pyridinyl[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds of Formula I: ##STR1## wherein R represents CH₂ CF₃ or (C₁ -C₃)alkyl optionally monosubstituted with F, Cl, or OCH₃ ;

Y and Z each independently represents H, F, Cl, Br, I, OCH₃, OC₂ H₅, CH₃ optionally mono to completely substituted with F;

V represents H, COR', CO₂ R", or CONR"'₂ ;

A and B each independently represents H, R', OR', S(O)_(n) R', F, Cl, Br, I, CN, NO₂, C₆ H₅, CO₂ R", or CONR'"₂ with the proviso that not more than one of A and B represents H;

D represents H, F, Cl, Br, I, CF₃, or CH₃ ;

n represents 0, 1, or 2;

R' represents (C₁ -C₄)alkyl optionally singly to completely substituted with fluorine;

R" represents (C₁ -C₄)alkyl, (C₃ -C₄)alkenyl, or (C₃ -C₄ ) alkynyl,

R"" represents H or (C₁ -C₄) alkyl; and when V represents H, the agriculturally acceptable salts thereof.

The compounds of the invention, usually in the form of an herbicidal composition containing one or more of them in admixture with an agriculturally acceptable adjuvant or carrier, exhibit strong herbicidal properties when applied either directly to the unwanted vegetation or to the locus thereof and when applied either preemergence or postemergence.

DETAILED DESCRIPTION OF THE INVENTION

The N-pyridinyl [1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds of the invention can be characterized as [1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds possessing an alkoxy substituent in the 5-position, alkyl, substituted alkyl, alkoxy, or halogen substituents in either or both of the 7- and 8-positions, and a substituted 3-pyridinyl moiety on the sulfonamide nitrogen atom. They are amides derived from a substituted [1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonic acid compound and a substituted 3-aminopyridine compound.

The compounds of the invention include those of Formula I: ##STR2## wherein R represents methyl, ethyl, propyl, 1-methylethyl, or cyclopropyl, each optionally monosubstituted with fluorine, chlorine or methoxy or represents 2,2,2-trifluoroethyl. Methyl and ethyl are typically preferred.

The Y and Z substituents of Formula I are independently selected and include hydrogen, methyl optionally mono to completely substituted with fluorine, or ethyl, fluoro, chloro, bromo, iodo, methoxy, or ethoxy. The substituents H, CH₃, F, Cl, and OCH₃ are typically preferred and compounds wherein one of Y and Z represents H, F, Cl, Br, I, CH₃, or OCH₃ and the other represents H are often more preferred.

The term V in Formula I generally represents hydrogen, CO(C₁ -C₄)alkyl optionally singly to completely substituted with fluorine, CO₂ (C₁ -C₄)alkyl, CO₂ (C₃ -C₄ )alkenyl, CO₂ (C₃ -C₄)alkynyl, CONH₂, CONH(C₁ -C₄)alkyl, or CON((C₁ -C₄)alkyl)₂. Hydrogen is typically preferred.

Substituents A and Bon the pyridine ring of the compounds of Formula I independently represent hydrogen, fluoro, chloro, bromo, iodo, cyano, nitro, phenyl, CO₂ (C₁ -C₄)alkyl, CO₂ (C₃ -C₄)alkenyl, or CO₂ (C₃ -C₄)alkynyl, CONH₂, CONH(C₁ -C₄)alkyl, or CON((C₁ -C₄)alkyl)₂, or represent (C₁ -C₄)alkyl, (C₁ -C₄)alkoxy, (C₁ -C₄)alkylthio, (Cl-C4)alkylsulfinyl, or (C₁ -C₄)alkylsulfonyl each optionally singly to completely substituted with fluorine, provided that at least one of A and B represents a substituent other than hydrogen. It is usually preferable that A and B both represent a substituent other than hydrogen. Methyl, ethyl, hydrogen, methoxy, ethoxy, propoxy, 1-methylethoxy, methoxycarbonyl, ethoxycarbonyl, fluoro, chloro, and bromo are often preferred substituents. The term D represents hydrogen, fluoro, chloro, bromo, iodo, trifluoromethyl, or methyl. It is often preferably hydrogen or methyl and is usually more preferably hydrogen. Compounds wherein A represents chloro, fluoro, or methoxy, B represents methyl, methoxy, ethoxy, propoxy, or 1-methylethoxy, and D represents hydrogen; or wherein A represents hydrogen, B represents methoxycarbonyl or ethoxycarbonyl, and D represents hydrogen are sometimes of special interest.

When V represents hydrogen, the compounds of Formula I are acidic and the invention includes the agriculturally acceptable salts.

The term alkyl as used herein includes straight chain, branched chain, and cyclic moieties. Thus, typical alkyl groups are methyl, ethyl, 1-methylethyl, propyl, cyclopropyl and the like. Methyl and ethyl are often preferred. Typical alkyl groups singly to completely substituted with fluorine include trifluoromethyl, monofluoromethyl, 2,2,2-trifluoroethyl, 2,3-difluoropropyl, and the like; trifluoromethyl is often preferred. Typical alkyl groups monosubstituted with methoxy or chloro include 2-chloroethyl, methoxymethyl, and 2-methoxy-1-methylethyl.

The term "agriculturally acceptable salts" is employed herein to denote compounds wherein the acidic sulfonamide proton of the compound of Formula I is replaced by a cation which itself is neither herbicidal to crop plants being treated nor significantly deleterious to the applicator, the environment, or the ultimate user of any crop being treated. Suitable cations include, for example, those derived from alkali or alkaline earth metals and those derived from ammonia and amines. Preferred cations include sodium, potassium, magnesium, and aminium cations of the formula:

    R.sup.6 R.sup.7 R.sup.8 NH.sup.⊕

wherein R⁶, R⁷, and R⁸ each, independently represents hydrogen or (C₁ -C₁₂)alkyl, (C₃ -C₁₂)cycloalkyl, or (C₃ -C₁₂)alkenyl, each of which is optionally substituted by one or more hydroxy, (C₁ -C₈)alkoxy, (C₁ -C₈)alkylthio or phenyl groups; provided that R⁶, R⁷, and R⁸ are sterically compatible. Additionally, any two of R⁶, R⁷, and R⁸ together may represent an aliphatic difunctional moiety containing 1 to 12 carbon atoms and up to two oxygen or sulfur atoms. Salts of the compounds of Formula I can be prepared by treatment of compounds of Formula I wherein V represents hydrogen with a metal hydroxide, such as sodium hydroxide, potassium hydroxide, or magnesium hydroxide, or an amine, such as ammonia, trimethylamine, hydroxyethylamine, bisallylamine, 2-butoxyethylamine, morpholine, cyclododecylamine, or benzylamine.

A listing of some typical compounds of the invention is given in Table 1. Some of the specifically preferred compounds of the invention include the following: N-(2-fluoro-4-methyl-3-pyridinyl)-5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide, N-(2-chloro-4-methoxy-3-pyridinyl)-5-methoxy-7-methyl[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide, N- (2-methoxy4-methyl-3-pyridinyl) -7-fluoro-5-methoxy[1,2,4]triazolo[1,5 -c]pyrimidine-2-sulfonamide, N- (2-chloro-4-methoxy-3-pyridinyl)-7-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]-pyrimidine-2-sulfonamide, N- (2-chloro -4-methyl -3-pyridinyl)-8-iodo-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide, and N- (2-chloro-4-methoxy-3-pyridinyl) -7-chloro-5-ethoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide.

                                      TABLE 1                                      __________________________________________________________________________     N-PYRIDINYL[1,2,4]TRIAZOLO[1,5-C]PYRIMIDINE-2-SULFONAMIDE COMPOUNDS             ##STR3##                                                                                                                    % C % H % N % S                  Cpd.                                     Melting                                                                             calc.                                                                              calc.                                                                              calc.                                                                              calc.                No. R    Y    Z   A     B     D   Form   point, °C.                                                                   found                                                                              found                                                                              found                                                                              found                __________________________________________________________________________      1  C.sub.2 H.sub.5                                                                     H    OCH.sub.3                                                                          Cl    H     H   white  225-226                                                                             40.6                                                                               3.41                                                                               21.8                                                                               8.33                                                   powder      40.3                                                                               3.61                                                                               21.5                                                                               8.12                  2  C.sub.2 H.sub.5                                                                     F    H   Cl    H     H   white  193-194                                                                             38.6                                                                               2.70                                                                               22.5                                                                               8.60                                                   crystals                                                                              (d)  38.7                                                                               2.69                                                                               22.4                                                                               8.73                  3  CH.sub.3                                                                            H    OCH.sub.3                                                                          CO.sub.2 CH.sub.3                                                                    H     H   white  187-189                                                                             42.6                                                                               3.58                                                                               21.3                                                                               8.13                                                   powder      42.4                                                                               3.53                                                                               21.3                                                                               8.11                  4  CH.sub.3                                                                            H    I   Cl    H     H   solid  197-200                                                                             25.4                                                                               1.38                                                                               17.4                                                                               7.97                                                          (d)  26.0                                                                               1.30                                                                               17.3                                                                               7.50                  5  CH.sub.3                                                                            H    I   CO.sub.2 CH.sub.3                                                                    H     H   pale yellow                                                                           183-186                                                                             31.9                                                                               2.26                                                                               17.1                                                                               6.54                                                   powder (d)  32.2                                                                               2.28                                                                               17.2                                                                               6.79                  6  C.sub.2 H.sub.5                                                                     F    H   CO.sub.2 CH.sub.3                                                                    H     H   white  182-183                                                                             42.4                                                                               3.31                                                                               21.2                                                                               8.09                                                   powder      42.4                                                                               3.35                                                                               21.2                                                                               7.94                  7  CH.sub.3                                                                            CH.sub.3                                                                            H   CO.sub.2 CH.sub.3                                                                    H     H   white  181-182                                                                             44.4                                                                               3.72                                                                               22.2                                                                               8.47                                                   powder      44.7                                                                               3.68                                                                               22.5                                                                               8.12                  8  CH.sub.3                                                                            H    OCH.sub.3                                                                          H     CO.sub.2 CH.sub.3                                                                    H   dihydrate                                                                             >300 (d)                                                                            39.0                                                                               4.22                                                                               19.5                                                                               7.45                                                   yellow      38.8                                                                               3.52                                                                               19.3                                                                               6.97                                                   powder                                        9  C.sub.2 H.sub.5                                                                     F    H   H     CO.sub.2 CH.sub.3                                                                    H   white  141-143                                                                             42.4                                                                               3.30                                                                               21.2                                                                               8.09                                                   powder      42.3                                                                               3.43                                                                               21.0                                                                               7.87                 10  C.sub.2 H.sub.5                                                                     F    H   Cl    CO.sub.2 CH.sub.3                                                                    H   tan    191-192                                                                             39.0                                                                               2.80                                                                               19.5                                                                               7.44                                                   powder (d)  39.1                                                                               3.00                                                                               18.7                                                                               6.78                 11  CH.sub.3                                                                            H    OCH.sub.3                                                                          Cl    CO.sub.2 CH.sub.3                                                                    H   tan    214-216                                                                             39.2                                                                               3.06                                                                               19.6                                                                               7.48                                                   powder (d)  39.5                                                                               2.97                                                                               19.7                                                                               7.28                 12  CH.sub.3                                                                            H    I   Cl    CO.sub.2 CH.sub.3                                                                    H   white  193-194                                                                             29.8                                                                               1.92                                                                               16.0                                                                               6.11                                                   powder (d)  30.2                                                                               1.83                                                                               16.2                                                                               6.06                 13  CH.sub.3                                                                            H    OCH.sub.3                                                                          Cl    CH.sub.3                                                                             H   off-white                                                                             196-199                                                                             40.5                                                                               3.40                                                                               21.8                                                                               8.32                                                   solid  (d)  40.6                                                                               3.62                                                                               21.9                                                                               8.11                 14  C.sub.2 H.sub.5                                                                     F    H   Cl    CH.sub.3                                                                             H   white  177-179                                                                             40.4                                                                               3.13                                                                               21.7                                                                               8.29                                                   solid  (d)  40.6                                                                               3.20                                                                               21.7                                                                               8.03                 15  CH.sub.3                                                                            H    OCH.sub.3                                                                          F     CH.sub.3                                                                             H   white  217-218                                                                             42.3                                                                               3.55                                                                               22.8                                                                               8.68                                                   powder (d)  42.5                                                                               3.50                                                                               22.6                                                                               8.84                 16  CH.sub.3                                                                            H    I   Cl    CH.sub.3                                                                             H   white  203-205                                                                             30.0                                                                               2.10                                                                               17.5                                                                               6.67                                                   powder      30.2                                                                               2.13                                                                               17.1                                                                               6.39                 17  CH.sub.3                                                                            H    CH.sub.3                                                                           Cl    CH.sub.3                                                                             H   pale yellow                                                                           207-208                                                                             42.3                                                                               3.55                                                                               22.8                                                                               8.69                                                   powder (d)  42.2                                                                               3.40                                                                               22.5                                                                               8.42                 18  CH.sub.3                                                                            Cl   H   Cl    CH.sub.3                                                                             H   pale yellow                                                                           193-194                                                                             37.0                                                                               2.59                                                                               21.6                                                                               8.23                                                   powder (d)  37.1                                                                               2.44                                                                               21.3                                                                               8.14                 19  CH.sub.3                                                                            H    Cl  Cl    CH.sub.3                                                                             H   white  212-214                                                                             37.0                                                                               2.59                                                                               21.6                                                                               8.23                                                   powder (d)  37.2                                                                               2.46                                                                               21.6                                                                               8.01                 20  C.sub.2 H.sub.5                                                                     F    H   F     CH.sub.3                                                                             H   white  188-189                                                                             42.2                                                                               3.27                                                                               22.7                                                                               8.66                                                   powder (d)  42.4                                                                               3.33                                                                               22.6                                                                               8.83                 21  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    CH.sub.3                                                                             H   white  200-201                                                                             42.3                                                                               3.55                                                                               22.8                                                                               8.69                                                   powder (d)  42.4                                                                               3.42                                                                               22.5                                                                               8.79                 22  CH.sub.3                                                                            H    F   Cl    CH.sub.3                                                                             H   white  203-204                                                                             38.7                                                                               2.70                                                                               22.5                                                                               8.60                                                   powder (d)  38.7                                                                               2.72                                                                               22.3                                                                               8.68                 23  CH.sub.3                                                                            H    H   Cl    CH.sub.3                                                                             H   white  199-201                                                                             40.6                                                                               3.13                                                                               23.7                                                                               9.04                                                   powder (d)  40.6                                                                               3.12                                                                               23.5                                                                               8.78                 24  CH.sub.3                                                                            H    Cl  F     CH.sub.3                                                                             H   white  204-205                                                                             38.7                                                                               2.90                                                                               22.5                                                                               8.60                                                   powder (d)  38.5                                                                               3.12                                                                               22.4                                                                               8.29                 25  CH.sub.3                                                                            Cl   H   F     CH.sub.3                                                                             H   white  182-183                                                                             38.7                                                                               2.90                                                                               22.5                                                                               8.60                                                   powder (d)  38.6                                                                               2.70                                                                               22.3                                                                               8.49                 26  CH.sub.3                                                                            H    F   F     CH.sub.3                                                                             H   tan    190-192                                                                             40.4                                                                               2.83                                                                               22.5                                                                               8.60                                                   powder (d)  40.4                                                                               3.15                                                                               22.3                                                                               8.49                 27  CH.sub.3                                                                            CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   white  194-195                                                                             44.3                                                                               3.72                                                                               23.9                                                                               9.10                                                   powder (d)  44.4                                                                               3.74                                                                               24.1                                                                               9.27                 28  CH.sub.3                                                                            H    OCH.sub.3                                                                          Cl    OCH.sub.3                                                                            H   white  196-197                                                                             39.0                                                                               3.27                                                                               21.0                                                                               8.00                                                   powder (d)  39.2                                                                               3.34                                                                               20.8                                                                               7.90                 29  CH.sub.3                                                                            H    I   F     CH.sub.3                                                                             H   white  194-196                                                                             30.9                                                                               2.16                                                                               18.0                                                                               6.86                                                   powder (d)  31.0                                                                               2.36                                                                               18.0                                                                               6.60                 30  C.sub.2 H.sub.5                                                                     F    H   Cl    OCH.sub.3                                                                            H   white  176-178                                                                             38.8                                                                               3.00                                                                               20.9                                                                               7.96                                                   powder (d)  38.6                                                                               2.95                                                                               20.8                                                                               7.90                 31  CH.sub.3                                                                            H    OCH.sub.3                                                                          Cl    Cl    H   white  215-216                                                                             35.6                                                                               2.49                                                                               20.7                                                                               7.91                                                   powder (d)  35.6                                                                               2.75                                                                               20.5                                                                               7.62                 32  C.sub.2 H.sub.5                                                                     F    H   Cl    Cl    H   white  196-197                                                                             35.4                                                                               2.23                                                                               20.6                                                                               7.87                                                   powder (d)  35.6                                                                               2.61                                                                               20.3                                                                               7.45                 33  CH.sub.3                                                                            H    CH.sub.3                                                                           F     CH.sub.3                                                                             H   white  206-207                                                                             44.3                                                                               3.72                                                                               23.9                                                                               9.10                                                   powder (d)  44.5                                                                               3.58                                                                               24.1                                                                               9.38                 34  CH.sub.3                                                                            H    H   F     CH.sub.3                                                                             H   white  194-195                                                                             42.6                                                                               3.28                                                                               24.8                                                                               9.48                                                   powder (d)  42.6                                                                               3.39                                                                               24.8                                                                               9.83                 35  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    OCH.sub.3                                                                            H   white  195-196                                                                             40.6                                                                               3.41                                                                               21.8                                                                               8.33                                                   solid  (d)  40.8                                                                               3.59                                                                               21.7                                                                               8.08                 36  CH.sub.3                                                                            F    H   OCH.sub.3                                                                            CH.sub.3                                                                             H   white  177-178                                                                             42.4                                                                               3.56                                                                               22.4                                                                               8.70                                                   powder (d)  42.3                                                                               3.64                                                                               22.8                                                                               7.92                 37  CH.sub.3                                                                            H    OCH.sub.3                                                                          OCH.sub.3                                                                            CH.sub.3                                                                             H   white  192-193                                                                             44.2                                                                               4.24                                                                               22.1                                                                               8.43                                                   powder (d)  44.2                                                                               4.41                                                                               22.4                                                                               8.43                 38  CH.sub.3                                                                            F    H   Cl    CH.sub.3                                                                             H   white  170-175                                                                             38.7                                                                               2.70                                                                               22.6                                                                               8.60                                                   powder (d)  38.8                                                                               2.76                                                                               21.3                                                                               7.93                 39  CH.sub.3                                                                            H    I   OCH.sub.3                                                                            CH.sub.3                                                                             H   white  195-197                                                                             32.8                                                                               2.75                                                                               17.7                                                                               6.73                                                   powder (d)  33.1                                                                               2.67                                                                               17.4                                                                               6.78                 40  CH.sub.3                                                                            H    OCH.sub.3                                                                          Br    CH.sub.3                                                                             H   tan    187-190                                                                             36.4                                                                               3.05                                                                               19.6                                                                               7.47                                                   powder (d)  36.7                                                                               3.18                                                                               19.4                                                                               7.83                 41  CH.sub.3                                                                            F    H   Br    CH.sub.3                                                                             H   white  180-182                                                                             34.6                                                                               2.42                                                                               20.1                                                                               7.68                                                   powder (d)  34.7                                                                               2.57                                                                               20.1                                                                               7.82                 42  CH.sub.3                                                                            CH.sub.3                                                                            H   Br    CH.sub.3                                                                             H   white  183-185                                                                             37.8                                                                               3.17                                                                               20.3                                                                               7.76                                                   powder (d)  38.0                                                                               3.56                                                                               19.9                                                                               8.05                 43  CH.sub.3                                                                            H    OCH.sub.3                                                                          SC.sub.2 H.sub.5                                                                     CH.sub.3                                                                             H   light yellow                                                                          176-178                                                                             43.9                                                                               4.42                                                                               20.5                                                                               15.6                                                   powder (d)  43.7                                                                               4.51                                                                               20.0                                                                               14.9                 44  CH.sub.3                                                                            F    H   SC.sub.2 H.sub.5                                                                     CH.sub.3                                                                             H   light gray                                                                            170-172                                                                             42.2                                                                               3.79                                                                               21.1                                                                               16.1                                                   powder (d)  42.5                                                                               3.94                                                                               20.9                                                                               15.8                 45  CH.sub.3                                                                            F    H   F     CH.sub.3                                                                             H   white  190-192                                                                             40.5                                                                               2.83                                                                               23.6                                                                               9.00                                                   powder      40.5                                                                               2.53                                                                               23.5                                                                               9.09                 46  CH.sub.3                                                                            OCH.sub.3                                                                           H   F     CH.sub.3                                                                             H   white  204-205                                                                             42.4                                                                               3.56                                                                               22.8                                                                               8.70                                                   powder (d)  42.3                                                                               3.67                                                                               22.6                                                                               8.94                 47  CH.sub.3                                                                            Cl   H   Cl    OCH.sub.3                                                                            H   white  183-185                                                                             35.6                                                                               2.49                                                                               20.7                                                                               7.91                                                   powder (d)  35.6                                                                               2.31                                                                               20.4                                                                               7.92                 48  CH.sub. 3                                                                           H    Cl  Cl    CH.sub.3                                                                             H   white  194-195                                                                             35.6                                                                               2.49                                                                               20.7                                                                               7.91                                                   powder (d)  35.7                                                                               2.38                                                                               20.5                                                                               7.89                 49  C.sub.2 H.sub.5                                                                     Cl   H   Cl    CH.sub.3                                                                             H   tan    188-189                                                                             38.7                                                                               3.00                                                                               20.8                                                                               7.95                                                   powder (d)  38.8                                                                               2.93                                                                               20.7                                                                               7.94                 50  C.sub.2 H.sub.5                                                                     Cl   H   F     CH.sub.3                                                                             H   tan    195-196                                                                             40.4                                                                               3.13                                                                               21.7                                                                               8.29                                                   powder (d)  40.5                                                                               3.04                                                                               21.7                                                                               8.53                 51  C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   Cl    OCH.sub.3                                                                            H   white  194-195                                                                             42.2                                                                               3.79                                                                               21.1                                                                               8.04                                                   solid       42.4                                                                               4.02                                                                               19.9                                                                               8.03                 52  CH.sub.3                                                                            H    Br  F     CH.sub.3                                                                             H   tan    189-191                                                                             34.6                                                                               2.42                                                                               20.1                                                                               7.68                                                   powder (d)  34.9                                                                               2.83                                                                               19.9                                                                               7.96                 53  C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   white  210-211                                                                             45.9                                                                               4.13                                                                               22.9                                                                               8.75                                                   powder (d)  46.1                                                                               4.17                                                                               23.1                                                                               8.94                 54  C.sub.2 H.sub.5                                                                     H    F   F     CH.sub.3                                                                             H   white  204-205                                                                             42.2                                                                               3.27                                                                               22.7                                                                               8.66                                                   powder (d)  42.2                                                                               2.87                                                                               22.4                                                                               8.77                 55  C.sub.2 H.sub.5                                                                     H    F   Cl    CH.sub.3                                                                             H   white  216-217                                                                             40.4                                                                               3.13                                                                               21.7                                                                               8.29                                                   powder (d)  40.5                                                                               2.97                                                                               21.7                                                                               8.11                 56  C.sub.2 H.sub.5                                                                     H    F   Cl    OCH.sub.3                                                                            H   white  205-207                                                                             38.8                                                                               3.00                                                                               20.9                                                                               7.96                                                   powder (d)  39.0                                                                               2.96                                                                               20.8                                                                               8.06                 57  CH.sub.3                                                                            F    H   Cl    OCH.sub.3                                                                            H   white  187-189                                                                             37.1                                                                               2.59                                                                               21.6                                                                               8.25                                                   powder (d)  37.3                                                                               2.46                                                                               21.5                                                                               8.22                 58  CH.sub.3                                                                            OCH.sub.3                                                                           H   Cl    OCH.sub.3                                                                            H   tan    197-199                                                                             39.0                                                                               3.27                                                                               21.0                                                       solid  (d)  38.9                                                                               3.40                                                                               20.9                     59  CH.sub.3                                                                            H    CH.sub.3                                                                           Cl    OCH.sub.3                                                                            H   tan    197-198                                                                             40.6                                                                               3.41                                                                               21.8                                                       solid  (d)  40.4                                                                               3.42                                                                               21.1                     60  CH.sub.3                                                                            CH.sub.2                                                                            H   F     CH.sub.3                                                                             H   white  199-200                                                                             44.0                                                                               3.95                                                                               22.0                                                                               8.38                          OCH.sub.3                powder (d)  43.9                                                                               3.92                                                                               21.8                                                                               8.50                 61  CH.sub.3                                                                            H    F   Cl    OCH.sub. 3                                                                           H   white  185-190                                                                             37.1                                                                               2.59                                                                               21.6                                                                               8.25                                                   powder (d)  37.1                                                                               2.38                                                                               21.4                                                                               8.25                 62  CH.sub.3                                                                            SCH.sub.3                                                                           H   Cl    OCH.sub.3                                                                            H   white  185-186                                                                             37.5                                                                               3.14                                                                               20.2                                                                               15.4                                                   powder (d)  37.5                                                                               3.26                                                                               20.2                                                                               15.2                 63  C.sub.2 H.sub.5                                                                     Cl   H   Cl    OCH.sub.3                                                                            H   white  183-184                                                                             37.2                                                                               2.89                                                                               20.0                                                                               7.65                                                   powder (d)  37.5                                                                               2.72                                                                               19.8                                                                               7.88                 64  CH.sub.3                                                                            F    H   F     H     CH.sub.3                                                                           white  178-179                                                                             40.5                                                                               2.83                                                                               23.6                                                                               9.00                                                   powder (d)  40.3                                                                               2.93                                                                               23.4                                                                               9.25                 65  CH.sub.3                                                                            CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   white  191-192                                                                             44.3                                                                               3.72                                                                               23.9                                                                               9.10                                                   powder (d)  44.2                                                                               3.82                                                                               23.9                                                                               9.36                 66  CH.sub.3                                                                            H    OCH.sub.3                                                                          F     H     CH.sub.3                                                                           white  174-176                                                                 solid  (d)                                   67  CH.sub.3                                                                            H    OCH.sub.3                                                                          H     CF.sub.3                                                                             H   light yellow                                                                          221-222                                                                             38.6                                                                               2.74                                                                               20.8                                                                               7.93                                                   solid       38.5                                                                               2.63                                                                               20.5                                                                               7.76                 68  CH.sub.3                                                                            CH.sub.3                                                                            H   H     CF.sub.3                                                                             H   white  193-194                                                                             40.2                                                                               2.86                                                                               21.6                                                                               8.26                                                   powder      40.0                                                                               2.66                                                                               21.7                                                                               8.43                 69  CH.sub.3                                                                            CH.sub.3                                                                            H   H     CO.sub.2 CH.sub.3                                                                    H   white  156-157                                                                             44.4                                                                               3.73                                                                               22.2                                                                               8.47                                                   powder      44.6                                                                               3.59                                                                               22.1                                                                               8.58                 70  C.sub.2 H.sub.5                                                                     F    H   F     H     Cl  tan    193-194                                                                             36.9                                                                               2.32                                                                               21.5                                                                               8.20                                                   powder (d)  37.1                                                                               2.43                                                                               21.4                                                                               7.98                 71  CH.sub.3                                                                            CH.sub.3                                                                            H   F     H     Cl  white  205-206                                                                             38.7                                                                               2.70                                                                               22.6                                                                               8.60                                                   powder (d)  38.5                                                                               2.57                                                                               22.5                                                                               8.60                 72  C.sub.2 H.sub.4 Cl                                                                  CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   tan    180-184                                                                 powder                                       73  CH.sub.2 CF.sub.3                                                                   CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   white  215-218                                                                             40.0                                                                               2.88                                                                               20.0                                                                               7.63                                                   powder      40.1                                                                               2.66                                                                               19.8                                                                               7.45                 74  CH.sub.3                                                                            CH.sub.3                                                                            H   H     CH.sub.3                                                                             H   white  188-190                                                                             46.7                                                                               4.22                                                                               25.1                                                                               9.59                                                   solid       46.8                                                                               4.06                                                                               24.9                                                                               9.87                 75  C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   H     CO.sub.2 CH.sub.3                                                                    H   white  180-181                                                                             45.9                                                                               4.11                                                                               21.4                                                                               8.17                                                   powder      46.2                                                                               4.01                                                                               21.6                                                                               8.34                 76  C.sub.2 H.sub.5                                                                     F    H   H     CH.sub.3                                                                             H   white  161-163                                                                             44.3                                                                               3.72                                                                               23.9                                                                               9.10                                                   powder      44.4                                                                               4.09                                                                               23.6                                                                               8.93                 77  CH.sub.3                                                                            F    OCH.sub.3                                                                          F     CH.sub.3                                                                             H   tan    177-180                                                                             40.4                                                                               3.13                                                                               21.8                                                                               8.30                                                   solid       40.7                                                                               3.61                                                                               21.1                                                                               8.05                 78  CH.sub.3                                                                            CH.sub.3                                                                            H   OCH.sub.3                                                                            CH.sub.3                                                                             H   white  215-216                                                                             46.2                                                                               4.43                                                                               23.1                                                                               8.80                                                   solid       46.3                                                                               4.56                                                                               23.2                                                                               8.36                 79  CH.sub.3                                                                            CH.sub.3                                                                            H   H     CO.sub.2 C.sub.2 H.sub.5                                                             H   white  152-153                                                                             45.9                                                                               4.12                                                                               21.4                                                                               8.17                                                   solid       45.5                                                                               4.24                                                                               21.5                                                                               8.12                 80  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    Cl    H   white  195-196                                                                             37.0                                                                               2.59                                                                               21.6                                                                               8.24                                                   solid  (d)  40.8                                                                               3.13                                                                               21.8                                                                               7.76                 81  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    C.sub.2 H.sub.5                                                                      H   white  202-203                                                                             42.2                                                                               3.79                                                                               21.1                                                                               8.04                                                   solid       42.4                                                                               3.38                                                                               21.1                                                                               7.72                 82  CH.sub.3                                                                            F    H   Cl    C.sub.2 H.sub.5                                                                      H   white  156-157                                                                             40.3                                                                               3.39                                                                               20.2                                                                               7.69                                                   solid       40.4                                                                               3.65                                                                               20.0                                                                               7.78                 83  CH.sub.3                                                                            CH.sub.3                                                                            H   H     CO.sub.2                                                                             H   white  158-159                                                                             47.3                                                                               4.46                                                                               20.7                                                                               7.89                                         C.sub.3 H.sub.7 (i)                                                                      solid       47.5                                                                               4.84                                                                               20.7                                                                               7.46                 84  CH.sub.3                                                                            CH.sub.3                                                                            H   H     C.sub.2 H.sub.5                                                                      H   white  184-186                                                                             46.2                                                                               4.43                                                                               23.1                                                                               8.08                                                   solid       46.5                                                                               4.37                                                                               22.8                                                                               7.98                 85  C.sub.2 H.sub.5                                                                     F    H   H     CO.sub.2                                                                             H   white  168-169                                                                             45.3                                                                               4.04                                                                               19.8                                                                               7.55                                         C.sub.3 H.sub.7 (i)                                                                      solid       45.5                                                                               4.20                                                                               19.6                                                                               7.48                 86  CH.sub.3                                                                            CH.sub.3                                                                            H   H     Cl    H   white  218-223                                                                             47.3                                                                               3.64                                                                               20.3                                                                               7.73                                                   solid  (d)  47.5                                                                               3.50                                                                               20.1                                                                               7.43                 87  CH.sub.3                                                                            H    OCH.sub.3                                                                          F     C.sub.2 H.sub.5                                                                      H   white  191-192                                                                             44.0                                                                               3.95                                                                               22.0                                                                               8.38                                                   solid  (d)  43.8                                                                               3.73                                                                               22.0                                                                               8.57                 88  C.sub.2 H.sub.5                                                                     F    H   F     C.sub.2 H.sub.5                                                                      H   white  192-193                                                                             43.8                                                                               3.67                                                                               21.9                                                                               8.34                                                   solid  (d)  43.8                                                                               3.57                                                                               21.8                                                                               8.57                 89  CH.sub.3                                                                            CH.sub.3                                                                            H   F     C.sub.2 H.sub.5                                                                      H   white  208-209                                                                             45.9                                                                               4.13                                                                               22.9                                                                               8.76                                                   solid       45.7                                                                               4.40                                                                               22.8                                                                               8.76                 90  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    OC.sub.3 H.sub.7 (n)                                                                 H   white  175-176                                                                             43.6                                                                               4.15                                                                               20.3                                                                               7.77                                                   solid       44.0                                                                               4.20                                                                               20.4                                                                               7.45                 91  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    OC.sub.3 H.sub.7 (i)                                                                 H   white  199-200                                                                             43.6                                                                               4.15                                                                               20.4                                                                               7.77                                                   solid       43.5                                                                               4.11                                                                               20.5                                                                               7.39                 92  C.sub.2 H.sub.5                                                                     F    H   Cl    OC.sub.3 H.sub.7 (n)                                                                 H   tan    159-160                                                                             41.8                                                                               3.74                                                                               19.5                                                                               7.44                                                   solid  (d)  41.9                                                                               3.83                                                                               19.4                                                                               7.72                 93  C.sub.2 H.sub.5                                                                     F    H   Cl    OC.sub.3 H.sub.7 (i)                                                                 H   white  181-182                                                                             41.8                                                                               3.74                                                                               19.5                                                                               7.44                                                   solid  (d)  41.6                                                                               3.96                                                                               18.9                                                                               7.58                 94  CH.sub.3                                                                            CH.sub.3                                                                            H   F     C.sub.3 H.sub.7 (i)                                                                  H   white  199-200                                                                             47.4                                                                               4.50                                                                               22.1                                                                               8.43                                                   solid  (d)  47.4                                                                               4.61                                                                               21.9                                                                               8.32                 95  CH.sub.3                                                                            F    H   Cl    OC.sub.3 H.sub.7 (i)                                                                 H   white  209-211                                                                             40.3                                                                               3.39                                                                               20.2                                                                               7.69                                                   solid  (d)  39.9                                                                               3.57                                                                               19.9                                                                               7.42                 96  C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   F     OC.sub.3 H.sub.7 (i)                                                                 H   white  212-213                                                                             45.0                                                                               4.49                                                                               19.7                                                                               7.51                                                   solid  (d)  44.9                                                                               4.40                                                                               19.5                                                                               6.65                 97  C.sub.2 H.sub.5                                                                     F    H   Cl    Cl    Cl  white  218-219                                                                             32.6                                                                               1.83                                                                               19.0                                                                               7.26                                                   solid  (d)  33.0                                                                               1.96                                                                               19.1                                                                               7.14                 98  CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    Cl    Cl  white  200-202                                                                             34.0                                                                               2.14                                                                               19.8                                                                               7.57                                                   solid  (d)  34.3                                                                               1.91                                                                               19.7                                                                               7.43                 99  CH.sub.3                                                                            H    Br  Cl    C.sub.2 H.sub.5                                                                      H   white  174-175                                                                             33.7                                                                               2.61                                                                               18.1                                                                               6.91                                                   solid  (d)  33.8                                                                               2.67                                                                               17.9                                                                               7.03                 100 CH.sub.3                                                                            H    Br  Cl    OCH.sub.3                                                                            H   white  194-197                                                                             32.1                                                                               2.24                                                                               18.7                                                                               7.13                                                   solid  (d)  32.2                                                                               2.30                                                                               18.8                                                                               7.00                 101 C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   Cl    C.sub.2 H.sub.5                                                                      H   white  196-198                                                                             43.6                                                                               4.15                                                                               20.4                                                                               7.77                                                   solid  (d)  43.6                                                                               4.26                                                                               20.2                                                                               7.92                 102 CH.sub.3                                                                            H    I   Cl    C.sub.2 H.sub.5                                                                      H   tan    184-185                                                                             30.6                                                                               2.37                                                                               16.5                                                                               6.28                                                   solid  (d)  30.7                                                                               2.39                                                                               16.0                                                                               5.46                 103 CH.sub.3                                                                            H    Cl  Cl    C.sub.2 H.sub.5                                                                      H   yellow 172-173                                                                             37.2                                                                               2.89                                                                               20.1                                                                               7.65                                                   solid  (d)  37.4                                                                               3.06                                                                               19.7                                                                               7.01                 104 C.sub.2 H.sub.5                                                                     CH.sub.3                                                                            H   Cl    OC.sub.3 H.sub.7 (n)                                                                 H   yellow 165-167                                                                             45.0                                                                               4.49                                                                               19.7                                                                               7.51                                                   solid  (d)  44.9                                                                               4.51                                                                               19.3                                                                               7.21                 105 CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    CO.sub.2 CH.sub.3                                                                    H   white  206-208                                                                             40.7                                                                               3.17                                                                               20.4                                                                               7.77                                                   solid  (d)  40.6                                                                               3.05                                                                               20.2                                                                               7.69                 106 CH.sub.3                                                                            C.sub.3 H.sub.7 (i)                                                                 H   F     CH.sub.3                                                                             H   orange 160-162                                                                             47.4                                                                               4.50                                                                               22.1                                                                               8.43                                                   solid       47.9                                                                               4.26                                                                               20.1                                                                               7.56                 107 C.sub.3 H.sub.7 (i)                                                                 CH.sub.3                                                                            H   Cl    OCH.sub.3                                                                            H   colorless                                                                             202-203                                                                             43.6                                                                               4.15                                                                               20.4                                                                               7.77                                                   solid  (d)  43.4                                                                               4.18                                                                               20.1                                                                               7.58                 108 C.sub.3 H.sub.7 (i)                                                                 CH.sub.3                                                                            H   F     CH.sub.3                                                                             H   tan    198-199                                                                             47.4                                                                               4.50                                                                               22.1                                                                               8.43                                                   solid  (d)  47.4                                                                               4.39                                                                               21.4                                                                               7.67                 109 C.sub.3 H.sub.7 (i)                                                                 CH.sub.3                                                                            H   Cl    OC.sub.2 H.sub.5                                                                     H   yellow 168-170                                                                             45.0                                                                               4.49                                                                               19.7                                                                               7.51                                                   solid       45.2                                                                               4.79                                                                               19.4                                                                               7.40                 110 CH.sub.3                                                                            CH.sub.3                                                                            H   F     OCH.sub.3                                                                            H                                                111 CH.sub.3                                                                            CH.sub.3                                                                            H   Br    OCH.sub.3                                                                            H                                                112 C.sub.2 H.sub.5                                                                     F    H   F     OCH.sub.3                                                                            H                                                113 C.sub.2 H.sub.5                                                                     F    H   Br    OCH.sub.3                                                                            H                                                114 C.sub.2 H.sub.5                                                                     F    H   F     OC.sub.2 CH.sub.3                                                                    H                                                115 C.sub.2 H.sub.5                                                                     F    H   OCH.sub.3                                                                            Cl    H                                                116 C.sub.2 H.sub.5                                                                     F    H   OCH.sub.3                                                                            CO.sub.2 CH.sub.3                                                                    H                                                117 C.sub.2 H.sub.5                                                                     F    H   Cl    OCH.sub.2 CF.sub.3                                                                   H                                                118 C.sub.2 H.sub.5                                                                     F    H   F     I     H                                                119 C.sub.2 H.sub.5                                                                     F    H   OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                             H                                                120 C.sub.2 H.sub.5                                                                     F    H   F     CO.sub.2 CH.sub.3                                                                    H                                                121 CH.sub.3                                                                            CH.sub.3                                                                            H   OCH.sub.3                                                                            Cl    H                                                122 CH.sub.3                                                                            CH.sub.3                                                                            H   OCH.sub.3                                                                            CO.sub.2 CH.sub.3                                                                    H                                                123 CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    OCH.sub.2 CF.sub.3                                                                   H                                                124 CH.sub.3                                                                            CH.sub.3                                                                            H   F     I     H                                                125 CH.sub.3                                                                            CH.sub.3                                                                            H   OC.sub.2 H.sub.5                                                                     CH.sub.3                                                                             H                                                126 CH.sub.3                                                                            CH.sub.3                                                                            H   Cl    OCH.sub.3                                                                            Cl                                               127 CH.sub.3                                                                            CH.sub.3                                                                            H   F     CO.sub.2 CH.sub.3                                                                    H                                                __________________________________________________________________________

The compounds of Formula I wherein V represents hydrogen can generally be prepared by combining a 2-chlorosulfonyl[1,2,4]triazolo[1,5-c]pyridine compound of Formula II: ##STR4## with an appropriately substituted aminopyridine compound of Formula III: ##STR5## in the presence of pyridine or a methylpyridine compound, and, optionally but preferably, a catalytic amount of dimethyl sulfoxide. The substituents OR, Y, and Z of Formula II and A, B, and D of Formulas III are as defined hereinbefore.

The preparation is usually accomplished by combining the 2-chlorosulfonyl[1,2,4]triazolo[1,5-c]pyrimidine compound Formula II, the aminopyridine of Formula III, and an inert solvent, such as acetonitrile, N,N-dimethylformamide, N-methyl2-pyrrolidinone, tetrahydrofuran, and the like, in a vessel and then adding the pyridine or methylpyridine, preferably pyridine, and a catalytic amount of dimethyl sulfoxide. The mixture is allowed to react, typically at ambient temperature, but with heating, if necessary. After a substantial quantity of the compound of Formula I has formed or a substantial quantity of the chlorosulfonyl compound of Formula II has been consumed, the desired product is recovered, typically removing the solvent by evaporation, adding water, and removing the liquids from the solid that forms by filtration or centrifugation. The product recovered can be purified, if desired, by extracting with an immiscible organic solvent, such as methylene chloride, and with water. Alternatively, the desired compounds of Formula I can be purified by recrystallization and by other commonly used methods.

Approximately equimolar quantities of the compounds of Formulas II and III are generally used in the preparation of compounds of Formula I although a substantial excess of one or the other may be employed. The pyridine or methylpyridine compound is generally employed in an amount of from at least 1 to about 5 moles per mole of compound of Formula II. Dimethyl sulfoxide is typically used in less than an equimolar amount; amounts over about 0.3 mole per mole of-compound of Formula II are usually deleterious. Acetonitrile is often the preferred solvent.

It is sometimes advantageous to prepare the compounds of Formula I by condensing a chlorosulfonyl compound of Formula II with an N-trialkylsilyl derivative of a substituted aminopyridine compound. The method employed is analogous to that described in U.S. Pat. No. 4,910,306 for N-trialkylsilylanilines. The reaction conditions required are essentially the same as those described hereinabove for the condensation of a compound of Formula II with a substituted aminopyridine with the exception that the pyridine compound base may be omitted. The substituted N-trialkylsilylaminopyridine compounds employed can be prepared from the corresponding substituted aminopyridine compounds by treatment with a trialkylsilyl halide and a trialkylamine as described in U.S. Pat. No. 4,910,306 for aniline compounds. Sodium iodide is typically employed as a catalyst when the halide is chloride. The N-trialkylsilylaminopyridine compounds are typically prepared and used immediately and without purification.

Compounds of Formula I wherein V represents hydrogen and OR represents (C₁ -C₃)alkoxy optionally monosubstituted with chloro or methoxy or 2,2,2-trifluoroethoxy can be made from the corresponding compounds related to those of Formula I wherein the moiety OR in the 5-position is replaced by chloro by treatment with an appropriate alkoxide reagent, such as sodium methoxide in methanol. The reaction conditions employed are similar to those used for the related exchange reactions of 2- and 4-chloropyrimidines. Non-aqueous media are preferred. Selective replacement of chlorine in the 5-position can readily be achieved as this chlorine is much more reactive than chlorine in the 7- and 8-positions (Y and/or Z represent Cl).

Compounds of Formula I wherein V represents COR', CO₂ R", or CONR"'₂ can be prepared from compounds of Formula I wherein V represents hydrogen by acylation with a compound of the formula ClCOR', ClCO₂ R", or ClCONR"'₂, respectively, using conventional procedures known in the art for the acylation of sulfonamides.

The 2-chlorosulfonyl[1,2,4]triazolo[1,5-c]pyrimidine compounds of Formula II and their analogs wherein the moiety OR is replaced by chloro can be prepared by the methods taught in U.S. Pat. No. 5,010,195.

The preparation of several substituted 3-aminopyridines, notably those wherein A represents chloro or fluoro, and B represents alkyl, alkoxy or alkylthio is described in the Examples. Other substituted 3-aminopyridines of interest as intermediates for the compounds of Formula I are known in the art or can be prepared by the general methods known in the art or provided herein.

While it is possible to utilize the [1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds of Formula I directly as herbicides, it is preferable to use them in mixtures containing an herbicidally effective amount of the compound along with at least one agriculturally acceptable adjuvant or carrier. Suitable adjuvants or carriers should not be phytotoxic to valuable crops, particularly at the concentrations employed in applying the compositions for selective weed control in the presence of crops, and should not react chemically with the compounds of Formula I or other composition ingredients. Such mixtures can be designed for application directly to weeds or their locus or can be concentrates or formulations which are normally diluted with additional carriers and adjuvants before application. They can be solids, such as, for example, dusts, granules, water dispersible granules, or wettable powders, or liquids, such as, for example, emulsifiable concentrates, solutions, emulsions or suspensions.

Suitable agricultural adjuvants and carriers that are useful in preparing the herbicidal mixtures of the invention are well known to those skilled in the art.

Liquid carriers that can be employed include water, toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl ketone, cyclohexanone, trichloroethylene, perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol monomethyl ether, methanol, ethanol, isopropanol, amyl alcohol, ethylene glycol, propylene glycol, glycerine, and the like. Water is generally the carrier of choice for the dilution of concentrates.

Suitable solid carriers include talc, pyrophyllite clay, silica, attapulgus clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite clay, Fuller's earth, cotton seed hulls, wheat flour, soybean flour, pumice, wood flour, walnut shell flour, lignin, and the like.

It is frequently desirable to incorporate one or more surface-active agents into the compositions of the present invention. Such surface-active agents are advantageously employed in both solid and liquid compositions, especially those designed to be diluted with carrier before application. The surface-active agents can be anionic, cationic or nonionic in character and can be employed as emulsifying agents, wetting agents, suspending agents, or for other purposes. Typical surface active agents include salts of alkyl sulfates, such as diethanolammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products, such as nonylphenol-C₁₈ ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol-C₁₆ ethoxylate; soaps, such as sodium stearate; alkylnaphthalenesulfonate salts, such as sodium dibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; and salts of mono and dialkyl phosphate esters.

Other adjuvants commonly utilized in agricultural compositions include antifoam agents, compatibilizing agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, penetration aids, spreading agents, sticking agents, dispersing agents, thickening agents, freeze point depressants, antimicrobial agents, and the like. The compositions can also contain other compatible components, for example, other herbicides, plant growth regulants, fungicides, insecticides, and the like and can be formulated with liquid fertilizers or solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like.

The concentration of the active ingredients in the herbicidal compositions of this invention is generally from about 0.001 to about 98 percent by weight. Concentrations from about 0.01 to about 90 percent by weight are often employed. In compositions designed to be employed as concentrates, the active ingredient is generally present in a concentration from about 5 to about 98 weight percent, preferably about 10 to about 90 weight percent. Such compositions are typically diluted with an inert carrier, such as water, before application. The diluted compositions usually applied to weeds or the locus of weeds generally contain about 0.001 to about 5 weight percent active ingredient and preferably contain about 0.01 to about 0.5 percent.

The present compositions can be applied to weeds or their locus by the use of conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation water, and by other conventional means known to those skilled in the art.

The compounds of Formula I have been found to be useful preemergence and postemergence herbicides. They can be employed at non-selective (higher) rates of application to control essentially all of the vegetation in an area or, in some cases, at selective (lower) rates of application for the selective control of undesirable vegetation in grass crops, such as corn, wheat, barley, and rice as well as in broadleaf crops, such as soybeans and cotton. While each of the N-pyridinyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide compounds encompassed by Formula I is within the scope of the invention, the degree of herbicidal activity, the crop selectivity, and the spectrum of weed control obtained varies depending upon the substituents present.

The term herbicide is used herein to mean an active ingredient which controls or adversely modifies the growth of plants. An herbicidally effective or vegetation controlling amount is an amount of active ingredient which causes an adversely modifying effect and includes deviations from natural development, killing, regulation, desiccation, retardation, and the like. The terms plants and vegetation are meant to include germinant seeds, emerging seedlings and established vegetation.

Herbicidal activity is exhibited by the compounds of the present invention when they are applied directly to the plant or to the locus of the plant at any stage of growth or before emergence. The effect observed depends upon the plant species to be controlled, the stage of growth of the plant, the application parameters of dilution and spray drop size, the particle size of solid components, the environmental conditions at the time of use, the specific compound employed, the specific adjuvants and carriers employed, the soil type, and the like, as well as the amount of chemical applied. These and other factors can be adjusted as is known in the art to promote selective herbicidal action. Generally, it is preferred to apply the compounds of Formula I postemergence to relatively immature plants to achieve the maximum control of broadleaf weeds.

Application rates of about 0.001 to about 1 Kg/Ha are generally employed in postemergence operations; for preemergence applications, rates of about 0.01 to about 10 Kg/Ha are generally employed. The higher rates designated generally give non-selective control of a broad variety of undesirable vegetation. The lower rates typically give selective control and, by judicious election, can be employed in the locus of crops.

EXAMPLES

The following Examples are presented to illustrate the various aspects of this invention and should not be construed as limitations to the claims.

1. Preparation of 3-Amino-2-fluoro-4-methylpyridine

To a solution of 10.1 g (grams) (65 mmol (millimole)) of 2-fluoro-4-methyl-3-nitropyridine in 200 mL (milliliter) of ethyl acetate was added 25 g (0.40 mol) of acetic acid and 0.8 g of 5 percent palladium on carbon catalyst. This mixture was shaken under 50 psig (pounds per square inch gauge, 2400 kiloPascals) pressure of hydrogen for 18 hours, was filtered, and was concentrated by evaporation under reduced pressure to obtain an oil. This oil was partitioned between dilute aqueous sodium bicarbonate and ether. The organic phase was separated, dried over magnesium sulfate, and filtered. The filtrate was concentrated by evaporation under reduced pressure and the residue was purified by column chromatography to obtain 7.2 g (88 percent of theory) of the title compound as a colorless solid melting at 63°-64° C.

Elemental Analysis C₆ H₇ FN₂ Calc.: %C, 57.1; %H, 5.59; %N, 22.2 Found: %C, 57.2; %H, 5.73; %N, 22.1 ¹ H NMR (nuclear magnetic resonance spectrum (200 megahertz)) CDCl₃ : 7.4 (d, 1H, J=5.0); 6.8 (d, 1H, J=5.0 ); 3.7 (br, 2H); 2.1 (s, 3H); 13C NMR CDCl₃ : 152.6 (d, J=229); 134.1 (d, J=8.6); 133.8 (d, J=14.5); 128.1 (d, J=27.1); 123.3, 16.4 (d, J=4.1).

3-Amino-2-fluoro-5-methylpyridine was prepared analogously from 2-fluoro-5-methyl-3-nitropyridine. This compound was obtained in 89 percent yield as white solid melting at 27°-28.5° C.

Elemental Analysis C₆ H₇ FN₂ Calc.: %C, 57.1; %H, 5.59; %N, 22.2 Found: %C, 56.9, %H, 5.65; %N, 22.6 ¹ H NMR CDCl₃ : 7.2 (d, 1H); 6.8 (d, 1H); 3.7 (br, 2H); 2.1 (s, 3H); ¹³ C NMR CDCl₃ : 151.8 (d, J=229); 134.5 (d, J=12.6); 132.2 (d, J=3.9); 129.9 (d, J=28.7); 125.8 (d, J=5.3), 17.8.

2. Preparation Of 3-Amino -2-chloro-4-methoxypyridine

To a solution of 6.4 g (51 mmol) of 3-amino-4-methoxypyridine in 30 mL of 37 percent aqueous hydrochloric acid was slowly added 7.8 g of 30 percent aqueous hydrogen peroxide at room temperature with stirring. After 30 min this solution was slowly poured into 300 mL of saturated aqueous sodium bicarbonate and the resulting mixture was extracted with ether (3×200mL). The ethereal extracts were combined, dried over magnesium sulfate, and filtered, The filtrate was concentrated by evaporation under reduced pressure to obtain a light brown solid. This solid was purified by column chromatography (17:83 acetone:hexane) to obtain 6.54 g (81 percent of theory) of the title compound as colorless needles melting at 86°-87° C.

Elemental Analysis C₆ H₇ ClN₂ O Calc.: %C, 45.4; %H, 4.45; %N, 17.7 Found: %C, 45.4; %H, 4.65; %N, 17.8 ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.4), 6.6 (d, 1H, J=5.4), 4.0 (br, 2H), 3.8 (s, 3H); ¹³ C NMR CDCl₃ : 153.3, 138.5, 135.6, 129.9, 105.2, 55.9.

3-Amino-2-chloro-4-ethoxypyridine was prepared from 3-amino-4-ethoxypyridine in an analogous procedure and was obtained as a white solid melting at 72°-73° C.

Elemental Analysis C₇ H₉ ClN₂ O Calc.: %C, 48.7; %H, 5.26; %N, 16.2 Found: %C, 48.9; %H, 4.98; %N, 16.5. ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.4), 6.6 (d, 1H, J=5.4), 4.1 (q, 2H, J=7.0), 4.0 (br, 2H), 1.5 (t, 3H, J=7.0).

3-Amino-2-chloro-4-propoxypyridine was prepared from 3-amino-4-propoxypyridine in an analogous procedure and was obtained as a white solid melting at 46°-47° C.

Elemental Analysis C₈ H₁₁ ClN₂ O Calc.: %C, 51.5; %H, 5.94; %N, 15.0 Found: %C, 51.8;o%H, 5.97; %N, 15.2 ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.4), 6.6 (d, 1H, J=5.4), 4.1 (br, 2H), 4.0 (t, 2H, J=6.5), 1.84 (m, 2H), 1.0 (t, 3H, J=7.4).

3 -Amino-2-chloro-4- (1-methylethoxy) pyridine was prepared from 3-amino-4-(1-methylethoxy)pyridine in an analogous procedure and was obtained as an amber oil.

Elemental Analysis C₈ H₁₁ ClN₂ O Calc.: %C, 51.5; %H, 5.94; %N, 15.0 Found: %C, 51.1; %H, 5.87; %N, 15.4 ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.5), 6.6 (d, 1H, J=5.4), 4.6 (m, 1H, J=6.0), 4.0 (br, 2H), 1.34 (d, 6H, J=6.0).

3. Preperation of 3-Amino-2-ethylthio-4-methylpyridine

2-Ethylthio-4-methyl-3-nitropyridine (10.0 g, 50.4 mmol) was added slowly with stirring to a solution of 57 g (0.25 mole) of stannous chloride in 250 mL of concentrated aqueous hydrochloric acid. An exothermic reaction took place. The solution was held at 70° C. for 30 min, cooled, and then poured slowly into saturated aqueous sodium bicarbonate solution. The resulting mixture was extracted with ether and the extract was dried over magnesium sulfate, filtered, and concentrated by evaporation under reduced pressure to obtain 5.8 g (68 percent of theory) of a light yellow oil that solidified upon standing. This solid was recrystallized from hexane to obtain 3.2 g of the title compound as a white solid melting at 37°-38° C.

Elemental Analysis C₈ H₁₂ N₂ S Calc.: %C, 57.1; %H, 7.19; %N, 16.7; %S, 19.1 Found: %C, 57.3; %H, 6.88; %N, 16.8; %S, 19.0 ¹ H NMR CDCl₃ : 7.8 (d, 1H, J=4.8), 6.7 (d, 1H, J=4.8), 3.8 (br, 2H), 3.2 (q, 2H, J=7.4), 2.1 (s, 3H), 1.3 (t, 3H, J=7.4). ¹³ C NMR CDCl₃ : 142.2, 139.5, 139.3, 128.9, 122.4, 25.4, 17.0, 15.0.

4. Preparation of Methyl 3-Amino-2-chloroisonicotinate

A mixture of 18 g (118 mmol) of methyl 3-aminoisonicotinate and 12 g (60 mmol) of 1,3-dichloro-5,5-dimethylhydantoin in 1500 mL of tetrachloroethylene was warmed slowly to 80° C. with stirring and held there for 3 hours. The solution was then cooled, filtered, washed with dilute aqueous sodium bicarbonate, dried over magnesium sulfate, filtered, and concentrated by evaporation under reduced pressure to obtain a dark oil. This oil was purified by careful column chromatography to give 6.7 g (30 percent of theory) of the title compound as a colorless solid melting at 91°-92° C.

Elemental Analysis C₇ H₇ ClN₂ O₂ Calc.: %C, 45.1; %H, 3.78; %N, 15.0 Found: %C, 45.2; %H, 3.94; %N, 15.1 ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.1); 7.6 (d, 1H, J=5.1); 6.2 (br, 2H); 3.9 (s, 3H); ¹³ C NMR CDCl₃ : 166.7, 141.9, 139.0, 134.7, 122.8, 116.5, 52.3.

5. Preparation of 3-Amino-4-ethyl-2-fluoropyridine

Trimethylsilyl chloride (2.2 g, (0.18 mmol) and sodium iodide (2.7 g, 0.18 mmol) were added to a solution of 3.6 g (0.15 mmol) of [-butyl N-(4-ethyl-2-fluoro-3-pyridyl)carbamate in 50 mL of dry acetonitrile with stirring at ambient temperature. After 2 hours the mixture was poured into ether and and the resulting solution was washed with dilute aqueous sodium bisulfite, dried over magnesium sulfate, and filtered. The filtrate was concentrated by evaporation under reduced pressure to obtain an oil. This oil was purified by column chromatography to obtain 1.6 g (76 percent of theory) of the title compound as a gold oil.

Elemental Analysis C₇ H₉ FN₂ Calc.: %C, 60.0; %H, 6.47; %N, 20.0 Found: %C, 59.8; %H, 6.66; %N, 20.2 ¹ H NMR CDCl₃ : 7.4 (d, 1H, J=5.0); 6.8 (d, 1H, J=5.0); 3.7 (br, 2H); 2.45 (q, 2H, J=7.5); 1.2 (t, 3H, J=7.5).

3-Amino-4-(1-methylethyl)-2-fluoropyridine was prepared in an analogous way from t-butyl N-(4-(1-methylethyl) -2-fluoro-3-pyridyl)carbamate. This compound was obtained in 92 percent yield as a gold oil.

Elemental Analysis C₈ H₁₁ FN₂ Calc.: %C, 62.3; %H, 7.19; %N, 12.3 Found: %C, 62.5; %H, 7.24; %N, 12.6. ¹ H NHR CDCl₃ : 7.4 (d, 1H, J=5.2); 6.8 (d, 1H, J=5.1); 3.8 (br, 2H); 2.87 (m, 1H); 1.2 (d, 6H, J=6.8).

6. Preparation of t-Butyl N-(4-Ethyl-2-fluoro-3-pyridyl)carbamate

A solution of lithium, diisopropylamine (LDA) was prepared from 19.3 mL (137 mmol) of diisopropylamine and 55 mL (137 mmo) of 2.5M n-butyllithium in hexane in 50 mL of dry tetrahydrofuran at -20° C. A solution of 14.4 g (62.5 mmol) of t-butyl N-(4-methyl-2-fluoro-3-pyridyl)carbamate in 80 mL of dry tetrahydrofuran was added dropwise with stirring at a rate slow enough to maintain the temperature below -60° C. After a 30 min reaction period, 27 g (190 mmol) of methyl iodide was added and the solution was allowed to warm to -10° C. The resulting mixture was diluted with 100 mL of aqueous ammonium chloride and 200 mL of ether and the phases were separated. The aqueous phase was washed with ether (3×100 mL). The organic phase and ether washes were combined, dried over magnesium sulfate, and filtered. The filtrate was concentrated by evaporation under reduced pressure to obtain a gold oil. This oil was purified by column chromatography to obtain 11.4 g (76 percent of theory) of the title compound as a white solid melting at 84°-86° C. ¹ H NMR CDCl₃ : 7.7 (d, 1H, J=5.08); 6.8 (d, 1H, J=5.08); 6.1 (br, 1H); 2.45 (q, 2H, J=7.6); 1.2 (s, 9H); 1.0 3H, J=7.6).

t-Butyl N- (4-(1-methylethyl)-2-fluoro-3-pyridyl )carbamate was prepared analogously from t-butyl N-(4-ethyl-2-fluoro-3-pyridyl)carbamate. This compound was obtained in 69 percent yield as a colorless solid melting at 60°-62° C.

Elemental Analysis C₁₃ H₁₉ FN₂ O₂ Calc.: %C, 61.4; %H, 7.53; %N, 11.0 Found: %C, 61.6; %H, 7.78; %N, 11.3. ¹ H NMR CDCl₃ : 7.9 (d, 1H, J=5.4); 7.0 (d, 1H, J=5.4); 6.0 (br, 1H); 3.2 (m, 1H); 1.4 (s, 9H); 1.2 (d, 6H, J=5.2).

7. Preparation of 3-Amino-2,4,5-trichloropyridine

Thirty percent aqueous hydrogen peroxide (3.0 g, 26 mmole) was added dropwise with stirring at 15° C. to a solution of 8.0 g (49 mmol) of 3-amino-4,5-dichloropyridine in 450 mL of 37 percent aqueous hydrochloric acid. After 30 min another 2.6 g (23 mmol) of 30 percent aqueous hydrogen peroxide was added and the solution was allowed to slowly warm to room temperature. The resulting mixture was diluted with water, neutralized with sodium carbonate, and extracted with ether. The ethereal extract was dried over magnesium sulfate and filtered. The filtrate was concentrated by evaporation under reduced pressure to obtain a viscous oil. This oil was partially purified by column chromatography to obtain 2.5 g (26 percent of theory) of the title compound, a white solid melting at 88°-90° C., and 5.3 g of a mixture of the title compound and 3-amino-2,4,5,6-tetrachloropyridine.

Elemental Analysis C₅ H₃ Cl₃ N₂ Calc.: %C, 30.4; %H, 1.53; %N, 14.2 Found: %C, 30.5; %H, 1.47; %N, 14.1. ¹ H NMR CDCl₃ : 7.7 (s, 1H); 4.6 (br, 2H).

8. Preparation of N-(2-Chloro-4-methoxy-3-pyridinyl)-7-fluoro-5-methoxy[1,2,4]triazolo[5-clpyrimidine-2-sulfonamide

To a solution of 5.4 g (33.8 mmol) of 3-amino-2-chloro-4-methoxypyridine and 3.0 g (11.3 mmol) of 2-chlorosulfonyl-7-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine in 20 mL of dry acetonitrile was added with stirring 0.91 mL (11.3 mmol) of dry pyridine and 0.16 mL (2.3 mmol) of dry dimethyl sulfoxide (DMSO). After 2 hours the resulting slurry was poured into a mixture of 200 mL of water and 800 mL of dichloromethane and the resulting mixture was stirred for 1 hour. The organic phase was recovered, dried over magnesium sulfate, filtered, and concentrated by evaporation under reduced pressure. The residue remaining was purified by flash column chromatography to obtain 1.6 g (38 percent of theory) of the title compound as a white solid melting at 187°-188° C.

Elemental Analysis C₁₂ H₁₀ ClFN₆ O₄ S Calc.: %C, 37.1; %H, 2.59; %N, 21.2; %S, 8.25 Found: %C, 37.3; %H, 2.46; %N, 21.5; %S, 8.22 ¹ H NMR DMSO-d₆ : 10.7 (br, 1H), 8.2 (d, 1H, J=5.7), 7.4 (s, 1H), 7.1 (d, 1H, J=5.7), 4.2 (s, 3H), 3.4 (s, 3H).

8. Preparation of N-(2-chloro-4-methoxy-3-pyridyl)-5,7-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide

To a solution of 0.60 g (1.5 mmol) of N-(2-chloro-4-methoxy-3-pyridinyl)-7-fluoro-5-methoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide in 20 mL of dimethyl sulfoxide was added with stirring 0.24 g (3.4 mmol) of potassium methoxide in 2.4 mL of dry methanol. After 1 hour 5 mL of acetic acid was added and the solution taken up in 400 mL of dichloromethane. The resulting solution was washed with water (6×150 mL), dried over magnesium sulfate, filtered, and concentrated by evaporation under reduced pressure to obtain 270 mg (20 percent of theory) of the title compound as a white solid melting at 197°-199° C. with decomposition.

Elemental Analysis C₁₃ H₁₃ ClN₆ O₄ S Calc.: %C, 39.0; %H, 3.27; %N, 21.0 Found: %C, 39.0; %H, 3.40; %N, 20.9 ¹ H NMR DMSO-d₆ : 10.6 (br, 1H); 8.2 (d, 1H, J=5.7); 7.1 (d, 1H, J=5.7); 6.7 (s, 1H); 4.2 (s, 3H); 3.9 (s, 3H); 3.4 (s, 3H).

9. Preparation of N-(4-Ethoxy-3-pyridinyl) -5-methoxy-7-methyl[1,2,4,]trriazolo[1,5-c]pyrimidine-2-sulfonamide

2-Chlorosulfonyl-5-methoxy-7-methyl[1,2,4]triazolo[1,5-c]pyrimidine (1.5 g, 5.7 mmol) was added to a solution of 0.8 g (5.7 mmol) of 3-amino-4-ethoxypyridine in 30 mL of dry pyridine in portions over 10 minutes with stirring. After 16 hours the reaction mixture was poured into 400 mL of dichloromethane. The resulting mixture was washed with 150 mL of water, dried over magnesium sulfate, and filtered. The filtrate was combined with 5 g of silica gel and the mixture was concentrated by evaporation under reduced pressure. The resulting silica plug was placed onto a 200 g silica gel column and eluted with dichloromethane containing increasing amount of ethanol. The product fractions were combined and concentrated by evaporation under reduced pressure and the solid obtained was dried to obtain 0.75 g (36 percent of theory) of the title compound as a white solid melting at 184°-186° C.

Elemental Analysis C₁₄ H₁₆ N₆ O₄ S Calc.: %C, 46.2; %H, 4.43; %N, 23.1; %S, 8.08 Found: %C, 46.5; %H, 4.37; %N, 22.8; %S, 7.98 ¹ H NMR (DMSO-d₆): 10.5 (br, 1H); 8.3 (s, 1H); 8.26 (d, 1H, J=5.6); 7.4 (s, 1H); 7.0 (d, 1H, J=5.6); 4.2 (s, 3H); 3.9 (q, 2H, J=7.0); 2.5 (s, 1H); 1.0 (t, 3H, J=7.0).

10. Evaluation of Postemergence Herbicidal Activity

Seeds of the desired test plant species were planted in Grace-Sierra MetroMix® 306 planting mixture, which typically has a pH of 6.0 to 6.8 and an organic matter content of about 30 percent, in plastic pots with a surface area of 64 square centimeters. When required to ensure good germination and healthy plants, a fungicide treatment and/or other chemical or physical treatment was applied. The plants were grown for 7-21 days in a greenhouse with an approximately 15 hr photoperiod which was maintained at about 23°-29° C. during the day and 22°-28° C. during the night. Nutrients and water were added on a regular basis and supplemental lighting was provided with overhead metal halide 1000 Watt lamps as necessary. The plants were employed for testing when they reached the first or second true leaf stage.

A weighed amount, determined by the highest rate to be tested, of each test compound was placed in a 20 mL glass vial and was dissolved in 4 mL of a 97:3 v/v (volume/volume) mixture of acetone and dimethyl sulfoxide to obtain concentrated stock solutions. If the test compound did not dissolve readily, the mixture was warmed and/or sonicated. The concentrated stock solutions obtained were diluted with an aqueous mixture containing acetone, water, isopropyl alcohol, dimethyl sulfoxide, Atplus 411F crop oil concentrate, and Triton X-155 surfactant in a 48.5:39:10:1.5:1.0:0.02 v/v ratio to obtain spray solutions of known concentration. The solutions containing the highest concentration to be tested were prepared by diluting 2 mL aliquots of the stock solution with 13 mL of the mixture and lower concentrations were prepared by dilution of appropriate smaller portions of the stock solution. Approximately 1.5 mL aliquots of each solution of known concentration were sprayed evenly onto each of the test plant pots using a DeVilbiss atomizer driven by compressed air pressure of 2 to 4 psi (140 to 280 kiloPascals) to obtain thorough coverage of each plant. Control plants were sprayed in the same manner with the aqueous mixture. In this test an application rate of 1 ppm results in the application of approximately 1 g/Ha.

The treated plants and control plants were placed in a greenhouse as described above and watered by sub-irrigation to prevent wash-off of the test compounds. After 2 weeks the condition of the test plants as compared with that of the untreated plants was determined visually and scored on a scale of 0 to 100 percent where 0 corresponds to no injury and 100 corresponds to complete kill. Some of the compounds tested, application rates employed, plant species tested, and results are given in Table 2.

                                      TABLE 2                                      __________________________________________________________________________     POSTEMERGENCE HERBICIDAL ACTIVITY                                                                              Wild                                           Cpd.                                                                              Rate,                                                                              Cockle-                                                                             Jimson-                                                                             Morning-                                                                            Velvet-   Buck-                                                                              Black-                                                                             Giant                                                                              Johnson-                           No.                                                                               ppm bur  weed glory                                                                               leaf Veronica                                                                            wheat                                                                              grass                                                                              foxtail                                                                            grass                              __________________________________________________________________________      1 1000                                                                               15   85   15   65   --   30  55   0  15                                  2 250 55   40   70   40   50   70  35   0   0                                  3 125 250  85   90   100  89   85  85  90  70                                  4 250 100  100  85   88   80   88  75  30  60                                  5 250 90   80   85   95   90   85  80  85  75                                  6 2000                                                                               80   85    0   85   30   80  50  60  15                                  7 1000                                                                               80   50   85   85   80   88  50  80  20                                  8 31.3                                                                               90   --   95   98   100  85  80  78  70                                  9 250 90   --   75   85   100  90  80  80  78                                 10 125 90   80   70   85   70   75  80  40  90                                 11 2000                                                                               75   80   75   70   98   70  80  78  75                                 12 1000                                                                               80   90   90   75   90   80  98  75  90                                 13  7.81                                                                              100  90   50   80   98   90  70  70  80                                 14 15.6                                                                               99   83   100  100   0   85  75  20  95                                 15  7.81                                                                              90   88   85   75   70   75  60  60  85                                 16 15.6                                                                               100  --   90   90   70   85  70  80  90                                 17 62.5                                                                               85   90   85   95   70   90  70  30  60                                 18 15.6                                                                               80   --   80   80   60   80  75  50  75                                 19  7.81                                                                              85   --   100  80   40   80  60  50  78                                 20  7.81                                                                              98   --   95   80    0   80  40   0  75                                 21  7.81                                                                              90   70   70   98   70   70  60  20  85                                 22 15.6                                                                               85   85   75   75   45   80  40  40  60                                 23 15.6                                                                               98   80   80   90   80   90  80  35  --                                 24 15.6                                                                               100  80   100  50   70   90  70  80  90                                 25 31.3                                                                               100  95   85   100  70   100 78  60  90                                 26 15.6                                                                               98   100  85   90   20   100 70  40   0                                 27 31.3                                                                               80   80   80   80    0   80   0   0  45                                 28 500 15   80   70   80   70   70  85  80  90                                 29 15.6                                                                               100  93   75   65   80   95  45  40  83                                 30 31.3                                                                               75   80   70   98   60   75  95  10  100                                31 500 80   80   70   80   90   75  85  75  85                                 32 125 90   80   70   85   40   80  80  45  75                                 33 125 70   80   80   80   85   85  75  30  40                                 34 15.6                                                                               99   80   80   80   100  98  20 45                                                                              80                                     35 31.3                                                                               90   85   88   85   88   85  90  85  88                                 36 125 70   88   90   85   100  86  90  85  84                                 37 62.5                                                                               85   90   90   89   100  80  89  85  85                                 38 15.6                                                                               88   80   85   88   75   88  75  80  80                                 39 250 75   70   85   95   95   95  90  90  90                                 40  7.81                                                                              83   95   70   83   100  75  60  40  75                                 41 31.3                                                                               70   80   85   93   70   93  80  20  83                                 42 31.3                                                                               100  70   75   80   100  100 70  70  85                                 43 125 85   80   88   100  75   85  50  50  85                                 44 500 50   75   85   85   50   85  70  20  75                                 45 31.3                                                                               --   --   90   88   70   80  50  85  90                                 46 31.3                                                                               --   --   88   88   88   88  75  70  95                                 47 62.5                                                                               75   80   85   80   80   78  80  65  80                                 48  7.81                                                                              90    0   85   80   80   80  70  70  90                                 49 15.6                                                                               100  88   88   80   80   80  40  40  85                                 50 15.6                                                                               100  88   90   85   70   84  35  30  85                                 51 31.3                                                                               90   90   88   88   90   80  88  90  80                                 52 15.6                                                                               90   --   85   70   75   85  55  70  85                                 53 15.6                                                                               90   --   88   85   88   88  55  70  100                                54 500 90   --   90   85   85   90  70  70  85                                 55 250 95   98   90   80   80   90  70  40  60                                 56 62.5                                                                               90   80   80   75   80   75  65  20  70                                 57 31.3                                                                               20   80   40   85   70   75  90  70  85                                 58 500 60   80   60   80   95   80  80  80  80                                 59 62.5                                                                               40   80   60   80   90   80  75  70  90                                 60 500 85   75   80   88   90   70  80  90  75                                 61 62.5                                                                               60   85   80   85   95   90  90  90  90                                 63 15.6                                                                               70   70   80   90   85   85  90  40  88                                 64 500 100  95   75   85   85   85  65  50  85                                 65 250 100  95   90   80   80   75  60  60  60                                 66 250 100  90   85   75   98   85  60  60  30                                 67 1000                                                                               99   70   45   40   85   75  45  10  60                                 68 1000                                                                               100  80   90   75   83   93  70  45  80                                 69 62.5                                                                               97   55   70   95   99   90  45  70  75                                 70 1000                                                                               97   83   95   75   70   70  80  65  20                                 71 500 100  90   95   85   83   50  50  65   0                                 72 62.5                                                                               100  80   100  90   90   85  80  70  100                                73 31.3                                                                               98   75   80   75   90   80  75  60  90                                 74 1000                                                                               85   75   80   80   85   83  75  70  99                                 75 250 100  75   75   90   90   80  85  100 75                                 76 1000                                                                               80   75   85   50   40   70  70  75  60                                 77 500 98   --   75   75   --   65  70  75  --                                 78 62.5                                                                               100  --   100  100  --   80  90  80  --                                 79 31.3                                                                               100  --   88   85   --   87  70  75  --                                 80 15.6                                                                               100  --   85   85   --   88  90  85  --                                 81  1.95                                                                              88   --   85   85   --   80  85  70  --                                 82 15.6                                                                               90   --   90   85   --   80  85  30  --                                 83 62.5                                                                               90   --   80   --   --   --  75  85  --                                 84 500 78   --   75   60   --   50  75  85  --                                 85 250 90   --   80   70   --   78  80  80  --                                 86 500 88   --   90   70   --   70  70  75  --                                 87 62.5                                                                               100  --   85   80   --   80  60  70  --                                 88 62.5                                                                               90   --   100  75   --   85  35  40  --                                 89 15.6                                                                               100  --   90   90   --   75  40  40  --                                 90 250 100  --   90   90   --   88  90  80  --                                 91 125 100  --   85   88   --   80  85  75  --                                 92 125 100  --   78   90   --   85  85  50  --                                 93 31.3                                                                               95   --   85   85   --   80  80  45  --                                 95 125 100  --   80   75   --   70  70  70  --                                 96  7.8                                                                               100  --   98   70   --   70  40  20  --                                 97 500 100  --   85   85   --   85  70  60  --                                 98 250 100  --   80   80   --   80  50  20  --                                 99 250 90   --   85   85   --   85  80  85  --                                 100                                                                               62.5                                                                               90   --   85   90   --   95  90  95  --                                 101                                                                               15.6                                                                               100  --   80   80   --   70  90  70  --                                 102                                                                               125 100  --   80   70   --   80  30  80  --                                 103                                                                               500 100  --   80   70   --   80  85  80  --                                 104                                                                               62.5                                                                               100  --   90   90   --   70  90  30  --                                 105                                                                               62.5                                                                               80   --   90   60   --   70  65  60  --                                 107                                                                               31.3                                                                               70   --   80   75   --   70  95  95  --                                 108                                                                               31.3                                                                               100  --   98   98   --   80  65  30  --                                 __________________________________________________________________________

11. Evaluation of Preemergence Herbicidal Activity

Seeds of the desired test plant species were planted in a soil matrix prepared by mixing a loam soil which was composed of about 43 percent silt, 19 percent clay, and 38 percent sand and had a pH of about 8.1 and an organic matter content of about 1.5 percent and sand in a 70 to 30 ratio. The soil matrix was contained in plastic pots with a surface area of 161 square centimeters. When required to ensure good germination and healthy plants, a fungicide treatment and/or other chemical or physical treatment was applied.

A weighed amount, determined by the highest rate to be tested, of each test compound was placed in a 20 mL glass vial and was dissolved in 8 mL of a 97:3 v/v (volume/volume) mixture of acetone and dimethyl sulfoxide to obtain concentrated stock solutions. If the test compound did not dissolve readily, the mixture was warmed and/or sonicated. The stock solutions obtained were diluted with a 99.9:0.1 mixture of water and Tween® 155 surfactant to obtain application solutions of known concentration. The solutions containing the highest concentration to be tested were prepared by diluting 4 mL aliquots of the stock solution with 8.5 mL of the mixture and lower concentrations were prepared by dilution of appropriate smaller portions of the stock solution. A 2.5 mL aliquot of each solution of known concentration was sprayed evenly onto the soil of each seeded pot using a Cornwall 5.0 mL glass syringe fitted with a TeeJet TN-3 hollow cone nozzle to obtain thorough coverage of the soil in each pot. Control pots were sprayed in the same manner with the aqueous mixture. A highest application rate of 4.48 Kg/Ha is achieved when 50 mg of test compound is employed.

The treated pots and control pots were placed in a greenhouse with an approximately 15 hr photoperiod which was maintained at about 23°-29° C. during the day and 22°-28° C. during the night. Nutrients and water were added on a regular basis and supplemental lighting was provided with overhead metal halide 1000 Watt lamps as necessary. The water was added by top-irrigation. After 3 weeks the condition of the test plants that germinated and grew as compared with that of the untreated plants that germinated and grew was determined visually and scored on a scale of 0 to 100 percent where 0 corresponds to no injury and 100 corresponds to complete kill or no germination. Some of the compounds tested, application rates employed, plant species tested, and results are given in Table 3.

                                      TABLE 3                                      __________________________________________________________________________     PREEMERGENCE HERBICIDAL ACTIVITY                                                                     Wild    Barn-                                            Cpd.                                                                              Rate,                                                                              Morning-  Velvet-                                                                             Buck-                                                                              Black-                                                                             yard                                                                               Giant                                                                              Johnson-                                 No.                                                                               Kg/Ha                                                                              glory                                                                               Pigweed                                                                             leaf wheat                                                                              grass                                                                              Grass                                                                              foxtail                                                                            grass                                    __________________________________________________________________________      2 1.12                                                                               40   50   75   60  70  60  50  50                                        3 0.56                                                                               85   80   80   80  70  90  95  20                                        4 1.12                                                                               90   100  85   98  10  95  75  75                                        5 2.24                                                                               60   75   85   85  25  98  98  20                                        8 0.56                                                                               50   90   80   90  90  90  98  50                                        9 1.12                                                                               80   95   85   90  80  98  98  90                                       10 1.12                                                                               85   90   95   90  98  95  75  --                                       11 4.48                                                                               50   100  98   30  100 100 60  100                                      13  0.035                                                                             90   100  95   --  90  65  90  90                                       14 0.14                                                                               80   98   95   90  85  95  80  --                                       15 0.14                                                                               90   85   90   90  85  90  90  90                                       16  0.018                                                                             40   100  90   100 80  90  80  --                                       17  0.035                                                                             80   98   95   50  70  90  20  --                                       18  0.035                                                                             80   95   80   50  90  95  30  --                                       19  0.018                                                                             80   90   90   80  50  80  60  --                                       20  0.035                                                                             90   90   80   80  80  95  50  --                                       21  0.018                                                                             80   98   80   70  60  95  60  --                                       22  0.035                                                                             90   85   95   80  70  85  20  --                                       23 0.14                                                                               80   90   95   90  30  0   60  60                                       24  0.070                                                                             90   100  70   90  90  98  100 90                                       25  0.070                                                                             60   100  80   75  60  98  20  85                                       26  0.035                                                                             90   100  85   95  90  90  60  80                                       27  0.035                                                                             60   100  95   90  95  98  80  80                                       28  0.056                                                                             50   98   98   80  98  98  98  75                                       29  0.070                                                                             80   90   80   85  75  100 75  90                                       30 0.14                                                                               95   90   95   85  98  98  50  98                                       31 1.12                                                                               50   75   50   30  75  75  50  75                                       32 0.56                                                                               98   98   85   90  98  98  50  98                                       33 0.28                                                                               90   95   80   95  75  60  40  80                                       34  0.070                                                                             75   100  90   90  50  50  70  80                                       35  0.070                                                                             80   95   85   80  100 70  90  90                                       36 0.28                                                                               85   60   85   90  100 98  90  90                                       37  0.018                                                                             80   80   75   90  90  98  80  85                                       38 0.28                                                                               90   98   95   98  90  85  95  98                                       39  0.035                                                                             40   90   85   98  80  90  85  90                                       40  0.018                                                                             90   100  90   --  40  60  75  90                                       41 0.28                                                                               90   100  98   --  85  90  95  90                                       42  0.035                                                                             90   100  95   --  50  40  60  90                                       43 0.56                                                                               90   30   75   90  95  98  60  90                                       45  0.035                                                                             70   98   80   88  40  70  85  85                                       46 0.28                                                                               40   90   60   70  0   60  65  85                                       47 0.14                                                                               40   90   80   87  95  75  80  80                                       48  0.009                                                                             60   95   70   75  80  90  70  90                                       49  0.070                                                                             90   98   85   95  75  90  78  90                                       50 0.14                                                                               90   98   85   95  65  98  65  90                                       51  0.070                                                                             88   90   90   85  95  80  85  88                                       52  0.035                                                                             90   90   75   90  65  80  70  90                                       53  0.009                                                                             90   85   85   88  85  90  75  88                                       54 0.14                                                                               90   85   85   90  60  70  45  80                                       55 0.56                                                                               90   90   65   90  70  65  30  80                                       56 0.28                                                                               85   80   75   80  40  40  30  65                                       57 0.56                                                                               75   80   85   50  80  55  80  90                                       58 1.12                                                                               65   95   80   55  95  70  75  90                                       59 0.14                                                                               75   90   90   90  75  70  90  90                                       60 1.12                                                                               100  90   65   70  98  80  65  80                                       61 0.14                                                                               90   98   88   90  10  70  90  80                                       63 0.14                                                                               70   90   85   90  95  95  80  95                                       64 1.12                                                                               80   80   60   80  98  60  75  95                                       65 0.56                                                                               80   60   70   50  99  80  80  90                                       66 0.56                                                                               90   70   60   70  90  90  90  70                                       67 0.28                                                                               20   70   30   65  90  70  30  80                                       68 0.28                                                                               65   80   50   85  100 90  80  90                                       69  0.070                                                                             85   90   75   90  60  70  70  75                                       70 1.12                                                                               30   50   40   20  30  85  95  50                                       71 2.24                                                                               75   90   50   40  50  90  70  60                                       72  0.070                                                                             50   90   50   60  50  50  60  90                                       73  0.035                                                                             70   70   70   80  85  95  90  90                                       74 1.12                                                                               60   90   50   50  50  70  50  90                                       75 0.56                                                                               80   95   80   90  80  85  95  50                                       77 0.28                                                                               40   50   50   --  70  70  90  --                                       78  0.070                                                                             85   95   95   --  95  98  90  --                                       79 0.28                                                                               85   75   90   --  85  85  95  --                                       80  0.070                                                                             80   85   98   --  98  20  95  --                                       81  0.070                                                                             90   90   90   --  95  80  85  --                                       82 0.28                                                                               95   50   80   --  100 95  60  --                                       83 0.28                                                                               90   80   70   --  85  95  60  --                                       84 2.24                                                                               85   90   65   --  90  65  70  --                                       85 1.12                                                                               75   50   75   --  80  75  60  --                                       87  0.070                                                                             80   60   85   --  80  95  85  --                                       88 0.14                                                                               80   80   90   --  80  95  80  --                                       89 0.14                                                                               85   75   85   --  85  90  80  --                                       90  0.070                                                                             90   90   95   --  95  85  70  --                                       91  0.070                                                                             85   85   90   --  95  90  95  --                                       92 0.56                                                                               75   80   90   --  95  95  75  --                                       93 0.14                                                                               85   75   90   --  98  95  25  --                                       94 0.28                                                                               60   40   25   --  70  75  70  --                                       97 1.12                                                                               90   85   70   --  60  70  50  --                                       98 1.12                                                                               78   90   85   --  65  80  75  --                                       101                                                                                0.035                                                                             85   80   85   --  85  85  75  --                                       102                                                                               0.28                                                                               35   70   80   --  90  95  80  --                                       103                                                                               0.28                                                                               35   65   80   --  85  85  60  --                                       104                                                                                0.070                                                                             85   80   95   --  95  75  50  --                                       105                                                                               0.14                                                                               90   90   85   --  90  70  75  --                                       108                                                                               0.14                                                                               90   74   95   --  85  90  75  --120                                    __________________________________________________________________________ 

What is claimed is:
 1. A 3-aminopyridine compound of the formula: ##STR6## wherein A represents F, B represents (C₁ -C₄)alkyl, and D represents H or wherein A represents F, Cl, or Br, B represents (C₁ -C₄)alkoxy, and D represents H.
 2. The compound according to claim 1: 3-amino-2-fluoro-4-methylpyridine.
 3. A compound according to claim 1 which is a 3-amino-2-chloro-4-(C₁ -C₄)alkoxypyridine. 